Question

If a car at rest accelerates uniformly to a speed of 144km/h in 20 sec., it covers a distance of * 1 point (a) 20 cm (b) 400 m (c) 1440 cm (d) 2980 cm

Answer 1

Answer:

b. 400m

Explanation:

v = u+ at

s = ut + 0.5 at^2

s= to be found

t= 20 sec

v= 144 km/h = 40m/s

u=0 m/s ( at rest )

a = v/t = 2 m/s^2

next, s = ut+ 0.5 at^2

=0 + 0.5 × 2× 20×20

= 400 m